As default we should have persistency settings for the standard relation instance identifing (RII) properties (see docmentation of PropertyRelationRuleBase.
The RII-properties follow the following naming schema: "MITK.Relations.<InstanceID>.[relationUID|destinationUID|ruleID|<data-layer-specific>]" - <InstanceID>: The unique index of the relation for the Source. Used to assign/group the properties to their relation. In the default implementation of this class the instance id is an positive integer (i>0). - relationUID: The UID of the relation. Set by the ID-layer (so by this class) - destinationUID: The UID of the Destination. Set by the ID-layer (so by this class) if Destination implements IIdentifiable. - ruleID: The identifier of the concrete rule that sets the property. Is specified by the derived class and set automaticaly be this base class. - <data-layer-specific>: Information needed by the Data-layer (so derived classes) to find the relationUID
The persistency settings should cover the default ones (relationUID, destinationUID and ruleID) and all RII properties that only have one data-layer-specific node.
E.g. "MITK.Relations.1.MyDataSpecific" would be covered, but not ""MITK.Relations.1.MyDataSpecific.2ndDataSpecificNode".
All other rule relevant properties must be covered by special persistency setting, defined by the implmenter of the rule.
Additional TODO: Fix wrong docu in PropertyRelationRuleBase. The naming schema for RII properties still contains <RuleID>.